The claimed invention relates to the field of circuit connectors, and more particularly to circuit connectors rated for a limited number of connect and disconnect cycles.
Electrical components in computers and complex machinery often are connected to each other and to power and control circuits by various types of electrical, or, increasingly, optical connectors rather than soldered or other semi-permanent means of connection. Some electrical connectors are ruggedly made and can be cycled through connections and disconnections innumerable times. Typical 2-to-3 prong connectors found commonly in hardware stores are examples of durable connectors. As the number of wires to be connected increase, then the expense of durable connectors increases significantly.
Many modern machine systems require multiple wiring harnesses to convey power and data between and among components. To minimize expense, inexpensive connectors rated for a minimal number of connect and disconnect cycles are often used. Thin wires, typically of 18-gauge and higher, are coupled to such inexpensive connectors singly or in wire ribbons. Coupling of the wire(s) to connectors terminals at a factory is typically accomplished by automated crimping of the attachment features of connector pins or sockets over and/or around the inserted wire. When using small gauge wires (18 Gauge or above), such crimped connections are typically limited to ratings of between 25 and 150 mating and unmating, or connect and disconnect, cycles. Failures occur for multiple reasons, including abrasive wear of contact materials through which circuits are completed within the connector, metal fatigue of the wires from being handled more than the rated number of cycles, fraying of the wires, metal fatigue of the crimped portions of the connector, and the loosening of the crimped fasteners from the connector pins and sockets after the rated number of cycles. Durability can vary greatly depending upon specific design features and materials used. For example, a connector using tin/lead connector compositions may be rated at 30 cycles while essentially the same connector using a gold connector composition may be rated 100 cycles or more. (See, e.g., Molex IDT™ connector 71694 and its data sheet description on the Molex website. Vendors such as Molex Incorporated and Tyco Electronics, a division of Tyco International, Ltd., (using its AMP brand) generally determine cycle ratings using standard protocols such as EIA (Electronic Industry Alliance) Standard 364-09, Revision C (1999) entitled “Durability Test Procedure For Electrical Connectors and Contacts”.
Groupings of wires, including ribbons of wires, with connectors at both ends form wire harnesses. Typically, one end connector is male and the other is female. Connectors at either end are rated based upon the number of mating and unmating cycles each such connector is expected to reliably endure. Wiring harnesses are a common and preferred means for routing power and data circuits since they can be pre-assembled in an off-line assembly system and then easily inserted into a machine system during machine manufacturing. During machine assembly, power and data wires from various subsystems are routed to a common connector in order to be ready for connection to a harness. Wires within the harness then connect the subsystems to power, data sources, and other appropriate subsystems.
Connectors at either end of wiring harnesses are prone to failure for reasons such as those described above. Harnesses with robust connectors are available but at a high cost. Harnesses with connectors rated for fewer than 100 cycles cost much less but still typically cost in excess of about $0.10 to about $0.20 for a 2-wire harness. If a connector is cycled more than its rated number of cycles, then good practice is to replace it. Replacement costs thus include the cost of replaced harness, labor to make the replacement, and wear and tear on the connectors that are connected to the replaced harness. Accordingly, it is desirable to require replacement of harnesses as infrequently as possible.
In complex systems such as middle and high-end printers and copiers, certain components are depleted or wear out with regularity. Since printing systems are designed to last a significant number of years, periodic replacement of exhausted subsystems requires that electrical or optical and mechanical connectors between the replaced subsystem and connected systems be cycled through many mating and unmating cycles during the life of the machine. For cost reasons, inexpensive electrical connectors are often used both as components of wire harnesses and as connectors to wire harnesses. In the typical useful life of a printer, many subsystems will require replacement and, periodically, many wiring harnesses with inexpensive connectors will need replacement or become the source of reliability problems.
It would be desirable to provide a set of inexpensive connectors that, although each is rated for a limited number of cycles, such connectors provide extended cycle life for wiring harnesses and connectors fastened thereto.
One embodiment of the present invention is a sacrificial circuit connector for interposition between male and female connector terminals for applications in which the expected connect and disconnect cycles may exceed the rated cycle limits of at least one of the connector terminals, said sacrificial connector comprising: a connector body having a male and a female connector side, at least one of such sides having connection compatibility to a connector terminal rated for cycle limits less than the number of cycles expected for the application; at least one circuit coupling element through which a circuit can be completed located on the male side; at least one circuit coupling element through which a circuit can be completed located on the female side; and a circuit conduit within the connector body for connecting the circuit between the female side coupling element and the male side coupling element; and wherein the male side is connection compatible with the female connector terminal and the female side is connection compatible with the male connector terminal.
Another embodiment is a process for extending the life of connector terminals, comprising: forming a connector body having a male and a female connector side, at least one of such sides having connection compatibility to a connector terminal rated for cycle limits less than the number of cycles expected for the application; locating on the male side at least one circuit coupling element through which a circuit can be completed; locating on the female side at least one circuit coupling element through which a circuit can be completed; enclosing at least one circuit conduit within the connector body for connecting the circuit between the female side coupling element and the male side coupling element; and connecting one side of the connector body to at least one connector terminal.
Another embodiment is an electrophotographic printer, comprising: a sacrificial circuit connector for interposition between male and female connector terminals for applications in which the expected connect and disconnect cycles may exceed the rated cycle limits of at least one of the connector terminals, said sacrificial connector comprising: a connector body having a male and a female connector side, at least one of such sides having connection compatibility to a connector terminal rated for cycle limits less than the number of cycles expected for the application; at least one circuit coupling element through which a circuit can be completed located on the male side; at least one circuit coupling element through which a circuit can be completed located on the female side; and a circuit conduit within the connector body for connecting the circuit between the female side coupling element and the male side coupling element; and wherein the male side is connection compatible with the female connector terminal and the female side is connection compatible with the male connector terminal.
Yet another embodiment is a sacrificial circuit connector for interposition between the connector terminals of a machine harness and a connector terminal for a component having a limited life for applications in which the expected connect and disconnect cycles may exceed the rated cycle limits of the machine harness connector terminal, said sacrificial connector comprising: means for connection compatibility with the machine harness connector terminal; means for connection compatibility with the connector terminal for the component; and a circuit conduit within the sacrificial connector for connecting the circuit between the machine harness connector terminal and the connector terminal for the component.